Inspection and Verification - Drive Cycle Test

The drive cycle test can be used as a system evaluation test, repair verification test, or during diagnosis (for intermittent concerns).

For system evaluation, the customer may only have a general concern about the way the vehicle is braking. There may not be a clear system concern to troubleshoot. This test is designed to produce common system concern symptoms. Once a symptom is found, a symptom troubleshooting procedure can be followed to repair the vehicle.

Always use this test after vehicle repairs because the ABS module is unable to detect some system concerns unless the vehicle is driven under specific conditions. After completing the drive cycle test, carry out the self-test using the diagnostic tool.

1. While driving the vehicle approximately 16 km/h (10 mph), apply the brake pedal hard enough to lock all four wheels.
2. Does one wheel lock consistently?
   • If yes and the yellow ABS warning indicator is not illuminated, GO to SYMPTOM CHART .
   • If yes and the yellow ABS warning indicator is illuminated, retrieve and document DTCs. Proceed to the ANTI-LOCK BRAKE SYSTEM (ABS) MODULE DIAGNOSTIC TROUBLE CODE (DTC) INDEX .
NOTE: If the pump motor turns on and the vehicle pulls immediately, the front wheel speed sensor opposite the pull should be checked using the ABS False Activation procedure from the Symptom Chart. If the pump motor turns on and the vehicle does not pull, the rear axle speed sensors should be checked using the ABS False Activation procedure from the Symptom Chart. If the pump motor does not turn on and the vehicle pulls immediately, the system should be checked using the Vehicle Pulls During Braking procedure from the Symptom Chart.
3. While driving the vehicle approximately 32 km/h (20 mph), carry out a light to medium (normal traffic) stop.
4. Does the pump motor turn on and are brake pedal pulsations felt at any time during the stop?
   • If yes and the yellow ABS warning indicator is not illuminated, GO to SYMPTOM CHART .
   • If yes and the yellow ABS indicator does illuminate, retrieve and document DTCs. Proceed to the ANTI-LOCK BRAKE SYSTEM (ABS) MODULE DIAGNOSTIC TROUBLE CODE (DTC) INDEX .
5. Clear continuous DTCs.
6. Start the vehicle and shift transmission into low gear.
7. Allow the vehicle to creep forward at idle for at least 45 seconds.
8. Does the yellow ABS indicator illuminate?
   • If yes, retrieve and document DTCs. Proceed to the ANTI-LOCK BRAKE SYSTEM (ABS) MODULE DIAGNOSTIC TROUBLE CODE (DTC) INDEX .
9. Slowly accelerate to 40 km/h (25 mph). Let at least 45 seconds elapse before reaching 40 km/h (25 mph).
10. Does the yellow ABS warning indicator illuminate?
    • If yes, retrieve and document DTCs. Proceed to the ANTI-LOCK BRAKE SYSTEM (ABS) MODULE DIAGNOSTIC TROUBLE CODE (DTC) INDEX .
11. Has the customer concern been addressed and corrected by the previous actions?
    • If yes, the system is OK.
    • If no, GO to SYMPTOM CHART .